School of Ecology and Environment, Inner Mongolia University, Hohhot, China.
School of Ecology and Environment, Inner Mongolia University, Hohhot, China; Key Laboratory of Forage Breeding and Seed Production of Inner Mongolia, Inner Mongolia M-Grass Ecology and Environment (Group) Co., Ltd., Hohhot 010016, China.
Sci Total Environ. 2023 Nov 1;897:165338. doi: 10.1016/j.scitotenv.2023.165338. Epub 2023 Jul 5.
Overgrazing generally induces dwarfism in grassland plants, and these phenotypic traits could be transmitted to clonal offspring even when overgrazing is excluded. However, the dwarfism-transmitted mechanism remains largely unknown, despite generally thought to be enabled by epigenetic modification. To clarify the potential role of DNA methylation on clonal transgenerational effects, we conducted a greenhouse experiment with Leymus chinensis clonal offspring from different cattle/sheep overgrazing histories via the demethylating agent 5-azacytidine. The results showed that clonal offspring from overgrazed (by cattle or sheep) parents were dwarfed and the auxin content of leaves significantly decreased compared to offspring from no-grazed parents'. The 5-azaC application generally increased the auxin content and promoted the growth of overgrazed offspring while inhibited no-grazed offspring growth. Meanwhile, there were similar trends in the expression level of genes related to auxin-responsive target genes (ARF7, ARF19), and signal transduction gene (AZF2). These results suggest that DNA methylation leads to overgrazing-induced plant transgenerational dwarfism via inhibiting auxin signal pathway.
过度放牧通常会导致草原植物矮化，即使排除过度放牧，这些表型特征也可以传递给克隆后代。然而，尽管普遍认为矮化传递机制是由表观遗传修饰所介导的，但这种机制在很大程度上仍然未知。为了阐明 DNA 甲基化对克隆跨代效应的潜在作用，我们通过去甲基化剂 5-氮杂胞苷，对来自不同牛/羊过度放牧历史的羊草克隆后代进行了温室实验。结果表明，与来自未放牧亲本的后代相比，来自过度放牧（牛或羊）亲本的克隆后代矮小，叶片中的生长素含量显著降低。5-azaC 的应用通常会增加生长素含量，促进过度放牧后代的生长，同时抑制未放牧后代的生长。同时，与生长素反应靶基因（ARF7、ARF19）和信号转导基因（AZF2）相关的基因表达水平也呈现出类似的趋势。这些结果表明，DNA 甲基化通过抑制生长素信号通路导致过度放牧诱导的植物跨代矮化。
